In most cases those /////// marks have been polished down by the old rope seal running on them, unless someone has just put them on the seal surface they probably will not have any adverse affect on you neoprene seal. When polishing a crank I will usually hit that pretty good with the belt.
God Bless.
Tim http://yblockguy.com/
350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor
tim@yblockguy.com Visalia, California Just west of the Sequoias